Performance Evaluation and Off-Design Strategy of a High Temperature Proton Exchange Membrane Fuel Cell Turbine-Less Hybrid System for Low Pressure Ratio and Mach Number Aircraft

The aviation industry is moving towards low-carbon and environment-friendly electric propulsion. This paper presents for the first time a high temperature proton exchange membrane fuel cell turbine-less hybrid system for low pressure ratio and Mach number aircraft. It is a new electric propulsion engine in which a plate reformer is used to supply hydrogen to the fuel cell. To investigate its performance and off-design strategies, thermodynamic, exergetic and exergoeconomic analyses models are established. Firstly, the thermodynamic performance is described and compared with that of a turbojet. Then, exergetic and exergoeconomic performances are revealed. Finally, the impact and comparison of four off-design strategies are studied in detail. The results show that the system can reduce specific fuel consumption by 24.90%. The burner, core nozzle and high temperature proton exchange membrane fuel cell need further development due to their low exergy efficiencies and high irreversibility ratios. The system has an exergoeconomic factor of 11.32%, relative cost difference of 24.65%, carbon dioxide mass specific emissions of 2.70 kg/(kW·h), and total system cost of 82.50 $/h. Strategy 2 is an economic option as it produces the minimum of specific fuel consumption, carbon dioxide mass specific emissions and total system cost.